Public transportation is becoming an increasingly important and complex means of transportation. For many individuals, public transportation is their only available means of transportation. Because they cannot drive, do not have a car, or have a physical or mental disability, these individuals must rely solely on public transportation. Many of these individuals are intimidated by the complexities of public transit, including identifying proper routes and transfer points according to schedule, and therefore remain trapped in their homes. For those with special needs, it is especially daunting to get from one location to another without any assistance, especially on their first few trips. Some of these individual have failing sight or hearing that can make it difficult for them to read the transit vehicle's schedule or hear the transit vehicle's driver announce stops. Many of these riders have varying degrees of mental or physical disabilities that requires another person to guide them through the process.
Transit agencies now employ “travel trainers,” whose sole job is to teach new riders with special needs how to successfully travel to and from a particular location using transit systems. Due to the amount of time required in teaching and monitoring individuals with various needs, there is often an extensive waiting list for such assistance from the travel trainers. Travel trainers ride with the individual until they feel that the rider can properly navigate the transit system on their own. At that point, the travel trainer will let the person ride by himself or herself for the first time. The travel trainer or family members usually follow the transit vehicle by car in order to guarantee that the rider makes it safely to their intended destination location. For those who successfully learn to navigate the transit system, often the caretaker of the individual is reluctant to allow them to travel without any supervision, usually due to the fear that the person may become lost and unable to return home.
Using public transit can be daunting even where a rider does would not be categorized as having special needs. Navigating the transit system can be a major obstacle for attracting new riders. A range of techniques from advertising to online trip planners to travel trainers is used by transit agencies to overcome this barrier to increase ridership. Research has found that current informational materials do not fully meet this need. According to the National Center for Transit Research (NCTR), approximately half of the general population surveyed could not successfully plan an entire trip on the fixed-route transit system using printed information materials. This situation is magnified for many of the fifty million Americans with disabilities who depend on transit systems as their primary means to and from school, work, doctor appointments, and other essential activities. For those with cognitive disabilities (approximately 14.2 million Americans, or 6.9% of the population), it is especially daunting to plan and execute a trip without any personal assistance from travel trainers provided by the transit agency or other group, especially on their first few trips.
With the proper software, Global Positioning System (GPS)-enabled mobile phones can be used as navigation devices for transit riders to aid the rider in exiting the vehicle at a proper transit stop. In this type of device, two forms of alerts are typically given to the rider: “Get Ready,” indicating that the rider's stop is approaching, and “Pull the Cord Now,” indicating that the rider should initiate a stop request by pulling a cord or pressing a button. Because of the limitations of computing resources on the mobile phone, which prevent advanced spatial queries, and the lack of regularly available complex spatial data from the transit agencies that would define the actual path the transit vehicle travels, transit stop detection methods on the mobile phone must be extremely efficient.
Simple geo-fencing methods may be utilized that detect when the device comes within a certain distance of the destination location. The diagram in FIG. 1 demonstrates a simple geo-fencing method. FIG. 1 shows starting location 10, the second-to-last scheduled stop, or triggering location 11, destination location 12, and real-time mobile device position 16. Optimally, destination geo-fence radius 14 is maximized in order to give an alert to the rider as soon as possible to allow him or her to prepare to exit the transit vehicle at destination location 12. However, in order to prevent the second alert, such as “Pull the Cord Now”, from being triggered too soon, the geo-fence radius 14 cannot exceed distance 15 between triggering location 11 and destination location 12. Because the actual travel distance between the locations is not known, the minimum possible distance between scheduled transit stops must be assumed using this type of method. Because there is uncertainty in calculated GPS positions, to use this method in the real world, GPS uncertainty value 13 must also be taken into account. Therefore, geo-fence radius 14 must be at least several meters less than the difference between GPS uncertainty value 13 subtracted from the distance between triggering location 11 and destination location 12 (or maximum geo-fence radius 14<distance 15−uncertainty value 13). This simple geo-fencing method results in challenges when attempting to give the transit rider timely alerts when transit stops are very close together. Additionally, because the method is limited by the minimum possible distance between the triggering location and destination location, a very early alert is not possible for locations that are far apart.
Accordingly, an improved method of detecting an approaching transit stop is needed that is more accurate and provides more timely alerts than those methods presently available.